public class Solution2 {
    //5. 最长回文子串
    public String longestPalindrome(String s) {
        int n = s.length();
        boolean[][] dp = new boolean[n][n];
        int len =  1;
        int begin = 0;
        for (int i = n-1; i >= 0; i--) {
            for (int j = i; j < n; j++) {
                if (s.charAt(i) == s.charAt(j)) {
                    dp[i][j] = i + 1 < j ? dp[i+1][j-1] : true;
                    if (dp[i][j] && j - i + 1 > len ) {
                        len = j - i + 1;
                        begin = i;
                    }

                }
            }
        }
        return s.substring(begin,begin+len);
    }
}
